Patent GB-190514468-A (GB)
Title: Improvements in Rock Drills and like Percussive Tools.
Inventor: JONES WILLIAM DAVID
Filed: 1905-07-13
Granted: 1906-08-13
Abstract: 14,468. Jones, W. D., Pierce, W. O., and Treglown, W. M. July 13. Percussive hand-tools.-A rock drill or like percussive tool of the type which has its tool rotated by fluid pressure, has a piston valve with three reduced portions, the central for admission and the others for exhaust, sliding in a sleeve having at least five series of ports. The handle of the tool, which forms a cap for the cylinder b and valve chamber c, is fixed at one end by a screw t and at the other end by a yoke s which passes round the other end of the valve chamber so as to fix the cap m<1>. On the cylinder flange u is mounted a cap v, carrying the tool-holder w, the cap being formed integral with a transverse cylinder k, Fig. 7, and being secured in a determined position by.the engagement of a pin on the flange with a corresponding hole in the cap, and the whole fixed by bolts v<5>, provided with springs v<6>, which press against a plate v<4>, internally coned so as to force a coned ring into contact with a shoulder on the tool-holder. Passages j, l which are in communication with opposite ends of the cylinder are by means of grooves in the cylinder flange connected with the ports j<1>, l<1>, Fig. 7, joined to opposite ends of the transverse cylinder. The caps z for this cylinder are fixed by bolts a<5> and springs a<6>, and the hollow piston y is provided at one end with an inner piston k<21>, which serves to act on the pivoted pawl C<1>, which rotates the ratchet tool-holder w, the stroke of the piston being limited by a stop D. When the piston is in the position shown in Fig. 1, fluid is led into the inlet port g through a tap cock, and passes through port e<4> in the valve sleeve, neck d<1>, and ports e<3>, g<3>, into the passage l, thence entering the space in front of the piston to drive it back by a port (not shown) at l<11>, and also passing through the port l<1>, Fig. 7, and port l<4>, so as to drive down the piston in the transverse cylinder, the exhaust in the main cylinder passing through ports g<6>, g<2>, e<6>, neck d<3>, and ports e<7>, i. When the front of the main piston h passes the port p<1>, and the neck h<1> comes opposite the ports o<2>, q<1>, fluid is exhausted from the larger or back end of the valve through ports e<8>, o, o<2>, neck h<1>, and ports q<1>, q into the atmosphere, and at the same time fluid passes through ports p<1>, p, and drives back the valve. In this position of the valve, to render it steady in working, the ports e<6> are put into connexion with the front of the valve through an annular groove in the valve, in which is a transverse.port passing into an axial hole a<3>. In this position also, the fluid is exhausted from the top of the transverse cylinder through the port l<5>. Fluid now enters port g and passes through ports e<4>, the neck d<1>, and ports e<5>, g<1>, g<6> behind the piston, which is driven out, the exhaust passing through ports l<11>, l, g<4>, e<2>, the neck d<2>, and ports e<1>, i. At the same time, fluid passes through the passage j, port j<1>, Fig. 7, port j<4>, and drives up the pistons y, k<21>, the pawl C' at the same time rotating the tool-holder w. When the rear end of tha piston uncovers the port o', the fluid passes through the ports o, e<8>, so as to return the valve. To fix the tool x in the holder, the spindle has an enlarged part x<2>, upon which is formed a projection having a curved face x<4>, which engages with a locking-bolt E, Fig. 8, having a cut-away portion E' and being pressed by a spring G, carried by a pin G', and by a loose recessed cap G<2>. The bore of the boss F is closed by a block H secured by a pin I'.